A sixth-century Byzantine cistern hidden below a modern carpet store.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

A marvel of Byzantine engineering under the streets of Istanbul.

Large miniature theme park with 100-plus models.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

This glass skywalk offers vertiginous views down the volcanic cliffs to the beach below.

This supermarket offers shoppers a window into the past alongside their groceries.

This bunker in northern France was built by Nazi German forces with the intention of launching up to 50 V2 rockets at London each day.

This ancient oak plays host to carvings of magical elves, gnomes, witches, and other creatures prominent in local folklore.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

Where royalty waits in the height of luxury.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

Sail in for a ’dam good slice.

Cat art as far as the eye can see.

This subterranean studio is filled with fascinating kinetic art.

These 4,444 wooden steps straight up a mountain were built to serve a hydroelectric power station but these days, they're mostly used by hikers.

A Dutch passageway's artistic, aquatic-themed makeover pays tribute to the capital city's famed waterways.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

A collection of art from Bulgaria's time as a communist state.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

Atop this former dutch railway office sits an interstellar work of art.